Abstract

To investigate the factors controlling nitrate-nitrogen dynamics during snowmelt season and rainfall events, this study was conducted in 3 adjacent headwater stream watersheds with coupled land use and topography characteristics in eastern Hokkaido, Japan. The agriculture-dominated watershed (AW) had flat topography in agricultural area, the forest-dominated watershed (FW) was characterized by a steep slope in forest area, and the mixed agriculture-forested watershed (AFW) had flat topography in the agricultural area and steep topography in the forest area. Results showed that the timing of nitrate-nitrogen export is different between the forested and steep watershed FW and the agricultural and flat watershed AW. The timing of nitrate-nitrogen export is related to subsurface flow